"One potential limitation of GFP as a reporter for gene expression
is its relatively slow rate of fluorescence acquisition in vivo limiting its use to experiments exceeding the hour time scale. The slow rate of fluorescence acquisition is reported to be
due to the oxidation step in chromophore formation (Figure
1), which has been estimated to occur with a time constant
of 2-4 h in vivo. (Heim et al., 1994)"